Re: numa_maps update

Andrew Morton
2006-03-04T09:07:08Z

Christoph Lameter <clameter@engr.sgi.com> wrote:
>
> Change the format

uh-oh.

> of numa_maps to be more compact and contain additional
> information that is useful for managing and troubleshooting memory on a NUMA
> system. Numa_maps can now also support huge pages.

What will be the userspace impact (ie: breakage) due to this change?

> New items shown:
>
> ...
> locked
> Number of pages locked. Only displayed if >0.

I doubt if the PageLocked() count will be useful. The only occasion upon
which pages are locked for more than a fleeting period is when they're
initially being brought up to date from backing store - readahead, swapin,
etc.

A more useful statistic would be the number of PageWriteback() pages.

> + if (file) {
> +
> + seq_printf(m, " file=");
> + seq_path(m, file->f_vfsmnt, file->f_dentry, "\n\t");
> +
> + } else if (vma->vm_start <= mm->brk &&
> + vma->vm_end >= mm->start_brk)
> +
> + seq_printf(m, " heap");
> +
> + else if (vma->vm_start <= mm->start_stack &&
> + vma->vm_end >= mm->start_stack)
> +
> + seq_printf(m, " stack");
> +
> + if (is_vm_hugetlb_page(vma)) {
> +
> + check_huge_range(vma, vma->vm_start, vma->vm_end, md);
> + seq_printf(m, " huge");
> +
> + } else

What bizarre layout!